US3304144A - Flash lamp manufacture - Google Patents

Description

1967 R. M. ANDERSON FLASH LAMP MANUFACTURE Filed April 50, 1965 lnven tov: RObEET I LATWdEFSQTW 5 i His ATFOT'TWEH United States Patent 3,304,144 FLASH LAMP MANUFACTURE Robert M. Anderson, Euclid, Ohio, assignor to General Electric Company, a corporation of New York Filed Apr. 30, 1965, Ser. No. 452,190 7 Claims. (Cl. 31620) This invention relates to a method of producing a photoflash lamp comprising a sealed glass bulb containing a quantity of readily combustible light-producing material in the form of sheet foil and a filling of a com bustion-supporting gas which, on ignition of the combustible material, reacts therewith to produce a momentary flash of actinic light of high intensity. More particularly, this invention relates to a method of inserting sheet foil combustible material in the shape of a cup ito such flash lamps during lamp manufacture.

Photoflash lamps that can be made by the process of the present invention are described and claimed in copending application Serial No. 452,189Anderson, filed concurrently with the present application. Those flash lamps are to some extent and for some purposes modifications of and improvements over photoflash lamps described and claimed in Patent 2,982,119Anderson which, in turn, canbe made by the processes of application Serial No. 91,279Anderson, filed December 3, 1963, now Patent 3,188,162, issued June 8, 1965. The patent and both of the applications are assigned to the assignee of the present application. Due to the relationships among these inventions, details of various equivalent acceptable methods of manufacture of flash lamps claimed in Patent 2,982,119 are described in Patent 3,188,162.

The flash lamps of application Serial No. 452,189 differ from those of Patent 2,982,119 in one basic way in that they contain sheet foil having a configuration and dimensions great enough that the foil resiliently contacts the inner wall of the flash bulb tending to hold the foil in position. In a similar manner, the method of manufacture of the present invention differs from that of Patent 3,188,162 in one principal manner in the process of loading the sheet foil combustible material into the lamp.

It is an object of the present invention to provide a method of manufacture for producing flash lamps of a tubular type containing sheet foil combustible material.

Another object of the invention is to provide such a process for lamps in which the sheet foil combustible material is in the form of a cup which opens towards ignition means in the lamp,

Still another object of the invention is to provide such a process for producing flash lamps in which the sheet foil combustible material is folded into the shape of a cup which is substantially further from the ignition means during sealing and afterwards than is filamentary combustible material also present in the flash lamp.

Still another object of the invention is to provide a process for producing tubular flash lamps containing both filamentary and sheet foil combustible material in which the sheet foil has a predetermined configuration and location within the lamp and is in contact with areas of the lamp wall.

Further objects and advantages of the invention will appear from the following detailed description of species thereof and from the accompanying drawing.

In the drawing, FIG. 1 is a partially sectioned front elevational view of a flash lamp made according to the invention.

FIG. 2 is a schematic illustration of several steps of the invention constituting a change from prior art methods of making flash lamps.

FIG. 3 is a side elevational view of a flash lamp in 3,304,144 Patented Feb. 14, 1967 manufacture according to one aspect of the invention after insertion of a foil cup and prior to final sealing by tipping off.

Briefly stated, the present invention in one embodiment provides a process for producing tubular photoflash lamps containing sheet foil combustible material in the form of a cup opening towards ignition means in the lamp. The process comprises the addition of certain steps to prior art processes of manufacturing photoflash lamps containing only filamentary combustible material such as described and claimed in Patent 3,188,162. The process of the present invention is applicable to the manufacture of flash lamps containing only sheet foil as the combustible material as well as to flash lamps containing a combination of both sheet foil and filamentary combustible material, which are described and claimed in copending application Serial No. 452,189. In the case of manufacturing photoflash lamps containing both filamentary combustible material and sheet foil combustible material the filamentary combustible material is added first to the open end of the lamp and positioned in proximity to the closed end of the lamp through which the leadin wires are sealed before adding the sheet foil. Thus, the filamentary combustible material will be generally closer to the ignition means than is the sheet foil. In this way, the filamentary material can aid in kindling the ignition of the sheet foil material. The additional steps that can be added to the processes of the prior art for the practice of the present invention follow: forming a foil cup from a sheet foil blank by pushing the blank into one end of a thin-wall tube, positioning the thinwall tube in relation to a glass lamp tube which has ignition means com-prising lead-in wires sealed through one end with the forming tube either adjacent to or within the lamp tube, and causing the foil cup to move from the forming tube into the lamp tube. The foil cup is then in close proximity to and opens toward the ignition means which are near the sealed end of the lamp tube. Subsequently, the lamp manufacture is completed by exhausting the lamp, filling the lamp with a combustion-supporting gas, and sealing off the lamp which may be done in any of the various ways known in the art.

The present invention not only provides a method for loading a piece of sheet foil combustible material into modern miniature photoflash lamps, but also allows a large degree of reproductibility at high manufacturing speeds. This is due in part to the foil cup having a predetermined geometry and position in the lamp and supporting itself on the inner wall of the lamp by resilient contact with the inner wall of the lamp, generally area rather than point contacts. Also, when filamentary combustible material, such as shredded foil, is present in the flash lamp in addition to the sheet foil, the foil cup serves to envelop, compact and hold in place the filamentary combustible material, preventing it from possibly being caught in the glass seal when the lamp is finally closed by tipping off.

Referring now to the drawing, FIG. 1 illustrates one construction of a photoflash lamp of the invention. Aside from the use of sheet foil material, the flash lamp illustrated is generally of a type described in detail in Patent 2,982,119. In general terms, the lamp comprises a stem press base 1 having electrical leads sealed therein, the external portions of which are retroverted and sealed back into the stem press as at 3 and folded back over opposite sides of the stem press at 4 to provide electrical contacts. The stem press base generally has a continuouly transverse slot 5 at one side to facilitate handling and utilization of the lamps. This base structure is described in further detail in Patent 3,016,727Vanden 3 Boom et al., assigned to the assignee of the present invention. Y e l The inner portions 2A of the lead wires 2 are held in position by a glass bead 6 and are electrically connected near their innermost ends by a filament such as of tungsten or tungsten-rhenium alloy wire. On the lead wires and the filament is located a fulminating primer material 8 which supplies ignition means to initiate the flashing of the lamp on the input of an electrical current through filament 7. Filament 7 heats very rapidly causing the fulminating primer to ignite. This ignition in turn causes the rapid combustion of filamentary combustible material 9 within the photoflash lamp-which, in turn, ignites the sheet foil combustible material 14.

The wall of. the lamp is formed from glass tubing 10, the base 1 having been formed at one end of the tubing. The other end of'the tubing is narrowed down at 11 to allow closure by formation of tip 12 after the rest of the assembly of. the inner parts of the lamp. After tipping, the flash lamp can be covered with a protective lacquer 13 as a safety feature to prevent explosion on flashing the lam A foil cup 14 of zirconium foil has been formed and positioned over the filamentary material 9, between the filamentary material 9 and the tip 12. The open end of the cup faces the ignition means which comprises the filament 7 and the fulminating primer 8. The foil cup 14 has a number of ears 15 that have been folded from the foil material in the production of the cup. These ears contact areas of the inner surface of the glass bulb wall giving some resilient support to the foil cup and tending to hold it in position.

FIG. 2 schematically illustrates a novel portion of the manufacturing process of the invention. As shown in position A, a sheet foil blank 20 is provided and positioned above a thin-wall forming tube 21. In position B, the sheet foil blank has been pushed into the forming tube 21 to form a foil cap 22. A plunger 26 slightly narrower than the forming tube would be satisfactory for pushing the foil blank 20 into the forming tube 21. Ears 23 will be left sticking out from the foil cap as shown if the foil blank 20 had angular corners such as a square foil blank would. On the other hand, if the foil blank used were round, the operation of pushing it into the forming tube 21 might cause the sides of the cup to have more of a corrugated configuration rather than folding relatively neatly into an earred cup.

At position C, the forming tube 21 is shown inserted into a lamp tube 24 with the end of the forming tube 21 containing the foil cap 22 in close proximity to ignition means 25 that have been provided thus far in the manufacture of the flash lamp. As described in connection with FIG. 1, a base 1 is illustrated as having been previously formed on the flash lamp. Lead wires 32 are shown prior to being bent down to provide electrical contacts as at 4 in FIG. 1. Also shown in this embodiment is a quantity of filamentary combustible material such as shredded zirconium foil made in accordance with the teachings of Rippl et al. Patent 2,351,290.

At D is shown a lamp tube of the invention in which foil cup 22 has been expelled from forming tube 21 into lamp tube 24 with ears 23 making resilient contact with the inner walls of the bulb tending to hold the foil cup 22 in position. The. forming tube 21 shown in position C has now been removed from the lamp tube, and the lamp tube 24 is now ready for further processing to complete its manufacture into a flash lamp. It will be understood that any appropriate means could be used to cause foil cup 22 to move out of the forming tube 21 and into the lamp tube 24. Plunger 27 is adapted to push the foil cup 22 into position. Suitable means might also include blowing with a stream of air or other gas.

FIG. 3 illustrates a further step in one process of manufacture of a flash lamp from lamp tube 24. As described more fully in Patent 3,188,162, the combustible material which, in this case, comprises filamentary shredded foil 9 in addition to sheet foil cup 22, is compressed into the lamp tube 24 somewhat away from the area 28 at which the lamp tube is heated and formed to make a dome before sealing by tipping ofi, This compression of the combustible material away from the glass to be heated for forming and tipping can be accomplished in the step in which the foil cup 22 is placed into the lamp tube 24.

After formation of the dome at 28, the lamp tube may be exhausted and then filled with a combustion-supporting gas through the necked down region 29 from apparatus which can be readily connected to tube 30. As is known in the art, various combustion-supporting gases may be used in photoflash lamps. Normally, they are oxygenous, although other gases such as carbon disulfide.

as shown in Patent 2,791,897Roth, assigned to the assignee of the present invention, can be used in certain circumstances. Alternatively, the lamp tube 24 can be broken off in the neck 29 and exhausting and filling accomplished by other means such as by operating on the lamp in an airtight chamber by evacuating the chamber.

and then filling it with the desired gas. Subsequently, the lamp tube 24 is sealed by tipping off at 31.

Aside from the novel method of forming foil cap 22 and inserting it into the lamp tube 24, other satisfactory techniques can be used for the preceding and succeeding portions of the lamp manufacturing process.

Stated in general terms, the overall process in which the process of the invention is used comprises the steps of sealing a lamp mount structure comprising a pair of lead-in wires in one end of a glass lamp tube to form a sealed end thereon, applying through the other end of said lamp tube a quantity of primer material, e.g., fulminating material, onto a portion of said lead-in wires within said lamp tube to form an ignition means, forming and placing inside the lamp according to the invention a sheet foil cup of combustible material, exhausting and introducing into the lamp tube through its open end a combustionsupporting gaseous medium, and then heating and sealing off the lamp tube at a position further from the sealed end than is the foil cup. Other embodiments of the invention provide for placing filamentary combustible material within the flash lamp before adding the foil cup, the requirement of a filament as part of the ignition means, and sealing off the lamp tube in an intermediate portion of its length located between its open end and the combustible foil material. In each case, the sheet foil combustible material has a configuration and dimensions larger than the inner transverse dimensions of the lamp tube so that the foil resiliently contacts the inner surface of the flash lamp tending to hold the foil in position. Preferably, the resilient contact is made with areas of the inner surface of the flash lamp. When filamentary combustible material is used inaddition to a sheet foil cup, the filamentary material is located proximate to the ignition means and envelops the same. This places the filamentary material in closer proximity to the ignition means than is the sheet foil cup, thereby allowing the fila-. mentary material to aid in igniting the foil cup.

While specific examples have been given of the process of the invention, it will be understood that various changes, omissions and substitutions may be made within the true spirit and scope of the invention as defined in the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. The method of making a flash lamp comprising the steps of sealing a lamp mount structure comprising a pair of lead-in wires into one end of a glass lamp tube to form a sealed end thereon, applying through the open other end of said lamp tube a quantity of primer material onto a portion of said lead-in wires Within said lamp tube to form an ignition means, forming a foil cup of sheet foil combustible material outside of said flash lamp by pushing a foil blank into a first end of a thin wall forming tube in one direction, said foil blank having dimensions in the plane of said foil substantially greater than the inside dimensions of said forming tube so that said foil blank is folded into a generally cup-shaped configuration on being pushed into said forming tube, said forming tube having transverse inner dimensions no larger than the transverse inner dimensions of said flash lamp, positioning the first end of said forming tube at least as close as adjacent to and aligned with said lamp tube, and causing said foil cup to move in the direction opposite said one direction out of said first end of said forming tube and through the open end of said lamp tube to a position proximate to the sealed end of said lamp tube so that said foil cup opens toward said ignition means, exhausting and introducing into the said lamp tube through its said open end a combustion-supporting gaseous medium, and then heating and sealing off said lamp tube at an area further from said scaled end than is said foil cup.

2. The method of claim 1 in which filamentary combustible material is inserted into the lamp tube before the foil cup is moved into the lamp tube so that said foil cup is generally further removed from the ignition means than is said filamentary combustible material.

3 The method of making a flash lamp comprising the steps of sealing a lamp mount comprising lead-in wires having a filament connected thereacross into one end of a glass lamp tube to form a sealed end thereon with said filament located a short distance inwardly of the lamp tube from its sealed end, applying through the open other end of said lamp tube a quantity of primer material onto the filament and the adjacent portions of said lead-in wire to form an ignition means, forming a foil cup of sheet foil combustible material outside of said flash lamp by pushing a foil blank into a first end of a thin wall forming tube in one direction, said foil blank having dimensions in the plane of said foil substantially greater than the inside dimensions of said forming tube so that said foil blank is folded into a generally cup-shaped configuration on being pushed into said forming tube, said forming tube having transverse inner dimensions no larger than the transverse inner dimensions of said flash lamp, positioning the first end of said forming tube at least as close as adjacent to and aligned with said lamp tube, and causing said foil cup to move in the direction opposite said one direction out of said first end of said forming tube and through the open end of said lamp tube to a position proximate to the sealed end of said lamp tube so that said foil cup opens toward said ignition means, exhausting and introducing into said lamp tube through its said open end a combustion-supporting gaseous medium, and then heating and sealing off an intermediate portion of the length of said lamp tube located between its said open end and the said combustible foil material.

4. The method of claim 3 in which filamentary combustible material is inserted into the lamp tube before the foil cup is moved into the lamp tube so that said foil cup is generally further removed from the ignition means than is said filamentary combustible material.

5. In a method of making a flash lamp comprising a glass lamp tube with ignition means sealed into one end thereof and having its other end open during manufacture and which contains sheet foil combustible material having a configuration and dimensions great enough so that the foil resiliently contacts areas of the inner surface of said flash lamp tending to hold the foil in position, the steps of:

(a) Forming a sheet foil blank which has dimensions in the plane of the foil blank greater than the transverse inner dimensions of said lamp tube,

(b) Pushing said sheet foil blank into a forming tube to form a foil cup, said forming tube having transverse inner dimensions no larger than those of said lamp tube,

(c) Positioning said forming tube at least as close as adjacent to and aligned with said open end of said lamp tube,

(d) Causing said foil cup to move into said lamp tube so that said foil cup opens towards said ignition means,

(e) Removing said forming tube from said lamp tube,

and

(f) Exhausting, filling with a combustion-supporting gas, and sealing said flash lamp.

6. In a method of making a flash lamp comprising a glass lamp tube with ignition means sealed into one end thereof and having its other end open during manufacture and which contains sheet foil combustible material having a configuration and dimensions great enough so that the foil resiliently contacts areas of the inner surface of said flash lamp tending to hold the foil in position, the steps of:

(a) Inserting filamentary combustible material into said lamp tube at the sealed end to envelop said ignition means, and

(b) Forming a sheet foil blank which has dimensions in the plane of the foil blank greater than the transverse inner dimensions of said lamp tube,

(c) Pushing said foil blank into a forming tube to form a foil cup, said forming tube having inner transverse dimensions no larger than those of said lamp tube,

(d) Positioning said forming tube at least as close as adjacent to and aligned with said open end of said lamp tube,

(e) Causing said foil cup to move into said lamp tube so that said foil cup opens towards said ignition means and is generally further removed from said ignition means than is said filamentary combustible material,

(f) Removing said forming tube from said lamp tube,

and

(g) Exhausting, filling with a combustion-supporting gas and sealing said flash lamp.

7. In the manufacture of a flash lamp comprising a glass lamp tube having ignition means sealed in a closed end thereof and having its other end open during manufacture, the steps which comprise forming a sheet foil blank of larger size than the diameter of said lamp tube, pushing said foil blank into one end of a forming tube which is of a diameter to fit snugly in said lamp tube to form a foil cup in said end of the forming tube, inserting said forming tube into the open end of said lamp tube with said one end of the forming tube foremost, and expelling said foil cup from the forming tube to cause it to be 10- cated in the lamp tube adjacent to and opening toward said ignition means.

No references cited.

RICHARD H. EANES, JR., Primary Examiner.

Claims (1)

1. THE METHOD OF MAKING A FLASH LAMP COMPRISING THE STEPS OF SEALING A LAMP MOUNT STRUCTURE COMPRISING A PAIR OF LEAD-IN WIRES INTO ONE END OF A GLASS LAMP TUBE TO FORM A SEALED END THEREON, APPLYING THROUGH THE OPEN OTHER END OF SAID LAMP TUBE A QUANTITY OF PRIMER MATERIAL ONTO A PORTION OF SAID LEAD-IN WIRES WITHIN SAID LAMP TUBE TO FORM AN IGNITION MEANS, FORMING A FOIL CUP OF SHEET FOIL COMBUSTIBLE MATERIAL OUTSIDE OF SAID FLASH LAMP BY PUSHING A FOIL BLANK INTO A FIRST END OF A THIN WALL FORMING TUBE IN ONE DIRECTION, SAID FOIL BLANK HAVING DIMENSIONS IN THE PLANE OF SAID FOIL SUBSTANTIALLY GREATER THAN THE INSIDE DIMENSIONS OF SAID FORMING TUBE SO THAT SAID FOIL BLANK IS FOLDED INTO A GENERALLY CUP-SHAPED CONFIGURATION ON BEING PUSHED INTO SAID FORMING TUBE, SAID FORMING TUBE HAVING TRANSVERSE INNER DIMENSIONS NO LARGER THAN THE TRANSVERSE INNER DIMENSIONS OF SAID FLASH LAMP, POSITIONING THE FIRST END OF SAID FORMING TUBE AT LEAST AS CLOSE AS ADJACENT TO AND ALIGNED WITH SAID LAMP TUBE, AND CAUSING SAID FOIL CUP TO MOVE IN THE DIRECTION OPPOSITE SAID ONE DIRECTION OUT OF SAID FIRST END OF SAID FORMING TUBE AND THROUGH THE OPEN END OF SAID LAMP TUBE TO A POSITION PROXIMATE TO THE SEALED END OF SAID LAMP TUBE SO THAT SAID FOIL CUP OPENS TOWARD SAID IGNITION MEANS, EXHAUSTING AND INTRODUCING INTO THE SAID LAMP TUBE THROUGH ITS SAID OPEN END A COMBUSTION-SUPPORTING GASEOUS MEDIUM, AND THEN HEATING AND SEALING OFF SAID LAMP TUBE AT AN AREA FURTHER FROM SAID SEALED END THAN IS SAID FOIL CUP.

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